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CN-121983645-A - Preparation method for improving mechanical strength of solid electrolyte membrane

CN121983645ACN 121983645 ACN121983645 ACN 121983645ACN-121983645-A

Abstract

The invention relates to the technical field of electrolyte membrane preparation, in particular to a preparation method for improving the mechanical strength of a solid electrolyte membrane, which solves the problems that a three-dimensional network structure with poor flexibility is destroyed and an ideal network supporting effect is difficult to realize in the subsequent dry rolling process because a proper nonpolar solvent is selected and the three-dimensional network of the existing electrolyte membrane is additionally subjected to drying treatment in the wet pouring process. The invention introduces a proper amount of oxide electrolyte with proper granularity and higher mechanical strength, and realizes higher mechanical strength of sulfide electrolyte membrane while ensuring higher ionic conductivity through a two-step dry mixing and dry rolling film forming process under the condition of properly optimizing the content of the binder.

Inventors

  • Lv Fengzheng

Assignees

  • 深圳固丰硅科新材料有限公司

Dates

Publication Date
20260505
Application Date
20260210

Claims (10)

  1. 1. The preparation method for improving the mechanical strength of the solid electrolyte membrane is characterized by comprising the following steps of: S1, filling an electrolyte initial material and a binder into a sample tube, and mixing to obtain a first dry mixed electrolyte material; s2, filling the oxide electrolyte and the first dry mixed electrolyte material into a sample tube, and mixing to obtain a second dry mixed electrolyte material; S3, fibrillating the secondary dry mixed electrolyte material in a grinding mode to obtain an initial blank; s4, transferring and placing the fibrillated initial blank on a release film, and rolling to form a solid electrolyte film; and S5, setting a comparison sample, performing synchronous tension test, recording tension change in real time, and feeding back the maximum tension value before fracture.
  2. 2. The method for producing a solid electrolyte membrane according to claim 1, wherein the electrolyte starting materials in S1 include, but are not limited to, sulfide electrolyte and halide electrolyte; sulfide electrolytes include, but are not limited to, li5.5ps4.5cl1.5, LPSC, sulfide glass ceramic type Li7P3S11, and lithium-free sulfide type Na3PS4, the LPSC being sulfur silver germanium ore type Li6PS5Cl; oxide electrolytes include, but are not limited to LLZO, LLTO, LAGP and LATP, the LLZO being lithium lanthanum zirconium oxide Li7La3Zr2O12, the LLTO being lithium lanthanum titanium oxide Li3xLa2/3-xTiO3, the LAGP being Li1.5Al0.5Ge1.5 (PO 4) 3, the LATP being Li1.3Al0.3Ti1.7 (PO 4) 3; The halide electrolyte includes, but is not limited to, the halide Li3MX6, where X is one or more of Cl, br, I, and M is one or more of Zr, hf, in, SC, Y, la, ce, pr, nb, sm, eu, gd, tb, dy, ho, er, tm, tb, lu; binders in S1 include, but are not limited to, polytetrafluoroethylene PTFE, polyvinylidene fluoride PVDF, polyacrylonitrile PAN, and polyvinyl alcohol PVA.
  3. 3. The method for producing a solid electrolyte membrane according to claim 2, wherein the mixing conditions in S1 and S2 are that the mixing is stopped every 3 minutes and continued 3 times at a rotation speed of 180 rpm; the grinding temperature conditions in S3 are carried out under the condition of 90 ℃; S4, the release film is made of polyethylene terephthalate PET; The rolling conditions in S4 are that the release film with the fibrillated initial blank placed thereon is rolled from the middle to the two ends by using a manual rolling mode on a horizontal heating table at 120 ℃, then the release film is rotated by 90 degrees and then rolled continuously, and the rolling operation is repeated until the film thickness reaches 100 mu m.
  4. 4. The method for preparing the solid electrolyte membrane with improved mechanical strength according to claim 3, wherein the preparation of the solid electrolyte membrane in S5 is performed according to the process of preparing the solid electrolyte membrane in S1 to S4, except that the preparation of the solid electrolyte membrane is performed by stopping the first dry mixed electrolyte material once again at 180rpm every 3min and continuously mixing for 3 times without adding oxide electrolyte into the second dry mixed electrolyte material, thereby obtaining the second dry mixed electrolyte material of the solid electrolyte membrane; The synchronous tension test in S5 is that a cutter is used for synchronously cutting the sulfide solid electrolyte membrane sample and the comparison sample into rectangular sample pieces with the size of 5cm x0.9cm, two terminals of a digital display type tension machine are used for clamping at the positions 1cm away from the two ends of the long side of each rectangular sample piece, the lengths of the stretched main bodies of the sulfide solid electrolyte membrane sample and the comparison sample are ensured to be 3cm, and the tension meter is lifted at a constant speed along the sliding shaft direction.
  5. 5. The method for preparing a solid electrolyte membrane according to claim 4, wherein the mass ratio of the oxide electrolyte is 0-20%, and the binder is 0-12% of the total weight of the powder to be solid electrolyte membrane.
  6. 6. The method for preparing a solid electrolyte membrane according to claim 5, wherein the mass ratio of the oxide electrolyte is 1-10%, and the binder is 0.5-8% of the total weight of the powder to be solid electrolyte membrane.
  7. 7. The method for preparing a solid electrolyte membrane according to claim 6, wherein the mass ratio of the oxide electrolyte is 1.5-5%, and the binder is 1-5% of the total weight of the powder to be solid electrolyte membrane.
  8. 8. The method for producing a solid electrolyte membrane according to any one of claims 5 to 7, wherein the particle size of the oxide electrolyte is controlled to 0 to 5. Mu.m.
  9. 9. The method for producing a solid electrolyte membrane according to claim 8, wherein the particle size of the oxide electrolyte is controlled to be 0.1 to 1. Mu.m.
  10. 10. The method for producing a solid electrolyte membrane according to claim 9, wherein the particle size of the oxide electrolyte is controlled to be 0.1 to 0.5. Mu.m.

Description

Preparation method for improving mechanical strength of solid electrolyte membrane Technical Field The invention relates to the technical field of electrolyte membrane preparation, in particular to a preparation method for improving the mechanical strength of a solid electrolyte membrane. Background The solid electrolyte membrane is used as a carrier for ion transmission in the all-solid battery, and plays an important structural component part for isolating the short circuit of the battery caused by direct contact of the anode and the cathode, so that the solid electrolyte membrane has a great significance for realizing commercial application of the high-specific-energy and high-safety solid battery. Thin and strong electrolyte membranes are critical to achieving high performance solid state batteries because electrolyte membranes do not provide battery capacity. Sulfide electrolyte has good flexibility, gradually softens when heated to about 60 ℃, and gradually increases cracks as the thickness of the electrolyte membrane decreases, severely restricting the integrity of the electrolyte membrane. At present, a three-dimensional network structure is usually formed in the industry, and then strong mechanical support and integrity of an electrolyte membrane are realized through a wet pouring or dry extrusion mode. The three-dimensional network is generally a polymer binder or electrolyte with poor ion conductivity and is prepared by a complex spinning process and a high-temperature sintering process or a high-speed fiberizing process. The existing three-dimensional network of the electrolyte membrane is subjected to wet pouring, not only is a proper nonpolar solvent selected, but also additional drying treatment is needed, and the three-dimensional network structure with poor flexibility is destroyed in the subsequent dry rolling process, and an ideal network supporting effect is difficult to realize, so that the existing requirements are not met, and a preparation method for improving the mechanical strength of the solid electrolyte membrane is provided. Disclosure of Invention The invention aims to provide a preparation method for improving the mechanical strength of a solid electrolyte membrane, which aims to solve the problems that in the background art, a three-dimensional network of the existing electrolyte membrane is required to be subjected to wet pouring, a proper nonpolar solvent is required to be selected, drying treatment is required to be additionally carried out, a three-dimensional network structure with poor flexibility is damaged in the subsequent dry rolling process, and an ideal network supporting effect is difficult to realize. In order to achieve the above purpose, the invention provides a preparation method for improving the mechanical strength of a solid electrolyte membrane, which comprises the following steps: S1, filling an electrolyte initial material and a binder into a sample tube, and mixing to obtain a first dry mixed electrolyte material; s2, filling the oxide electrolyte and the first dry mixed electrolyte material into a sample tube, and mixing to obtain a second dry mixed electrolyte material; S3, fibrillating the secondary dry mixed electrolyte material in a grinding mode to obtain an initial blank; s4, transferring and placing the fibrillated initial blank on a release film, and rolling to form a solid electrolyte film; and S5, setting a comparison sample, performing synchronous tension test, recording tension change in real time, and feeding back the maximum tension value before fracture. Preferably, the electrolyte starting materials in S1 include, but are not limited to, sulfide electrolytes and halide electrolytes; sulfide electrolytes include, but are not limited to, li5.5ps4.5cl1.5, LPSC, sulfide glass ceramic type Li7P3S11, and lithium-free sulfide type Na3PS4, the LPSC being sulfur silver germanium ore type Li6PS5Cl; oxide electrolytes include, but are not limited to LLZO, LLTO, LAGP and LATP, the LLZO being lithium lanthanum zirconium oxide Li7La3Zr2O12, the LLTO being lithium lanthanum titanium oxide Li3xLa2/3-xTiO3, the LAGP being Li1.5Al0.5Ge1.5 (PO 4) 3, the LATP being Li1.3Al0.3Ti1.7 (PO 4) 3; The halide electrolyte includes, but is not limited to, the halide Li3MX6, where X is one or more of Cl, br, I, and M is one or more of Zr, hf, in, SC, Y, la, ce, pr, nb, sm, eu, gd, tb, dy, ho, er, tm, tb, lu. Binders in S1 include, but are not limited to, polytetrafluoroethylene PTFE, polyvinylidene fluoride PVDF, polyacrylonitrile PAN, and polyvinyl alcohol PVA. Preferably, the mixing conditions in S1 and S2 are that the mixing is stopped once every 3min and continuously performed 3 times under the condition of rotating speed of 180 rpm; the grinding temperature conditions in S3 are carried out under the condition of 90 ℃; S4, the release film is made of polyethylene terephthalate PET; The rolling conditions in S4 are that the release film with the fibrillated initi